Cosmic SuperFly Speed Wheels. An inexpensive wheel with an open hub which is grippy for slippery floors or outdoor surfaces. This hub design reduces weight, while the 90a urethane durometer offers extra grip. This is a wide wheel, 44mm for best balance at high speed.

These have great traction, at a remarkable price. I often get in speed races with my kid and while her soft Rollerblade wheels are gripping my old wheel would start sliding, Not with these, they stick to the indoor surface like glue when I need it.